Melenbacher Adyn, Dhindsa Jasveer S, Gilroy Joe B, Stillman Martin J
Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Angew Chem Int Ed Engl. 2019 Oct 21;58(43):15339-15343. doi: 10.1002/anie.201908999. Epub 2019 Sep 12.
Boron difluoride (BF ) formazanate dyes are contenders for molecular species that exhibit a large Stokes shift and bright red emission. Excitation of 3-cyanoformazanate complexes with 10 μs wide pulses of specific wavelengths resulted in strong luminescence at 663 nm at both room temperature in solution and at 77 K in a frozen solution. Analysis of the short-lived excitation spectrum from this luminescence shows that it arises from a vibronic manifold of a higher-lying excited state. This dark state relaxes to the emitting state over 10 μs. TD-DFT calculations of the two lowest-energy excited states show that the relaxed geometries are planar for S but highly distorted in S . The specific time- and wavelength-dependence of the excitation profile provides a unique optical encryption capability through the comparison of emission intensities between adjacent vibronic bands only accessible in the 0-12 μs time domain.
二氟化硼（BF）甲臜染料是具有大斯托克斯位移和亮红色发射的分子种类的有力竞争者。用特定波长的10微秒宽脉冲激发3-氰基甲臜配合物，在室温下的溶液中和77K的冷冻溶液中均在663nm处产生强烈发光。对该发光的短寿命激发光谱分析表明，它源于较高激发态的振动电子态。这种暗态在10微秒内弛豫到发射态。对两个最低能量激发态的TD-DFT计算表明，S态的弛豫几何结构是平面的，而S态则高度扭曲。激发轮廓的特定时间和波长依赖性通过仅在0-12微秒时域内可访问的相邻振动电子带之间发射强度的比较提供了独特的光学加密能力。
